Furnace stoker



FURNACE STOKER Filed Dec. 14, 1936 3 Sheets-Sheet 1 INVENTOR.

LEONA/P0 A WARD.

March 21, 1939. Y L. A. WARD 2,151,575

FURNACE STOKER Filed Dec. 14, 1936 3 Sheets-Sheet 2 INVENTOR. LEO/V490 A. WARD March 21, 1939. L, A. WARD FURNACE STOKER Filed Dec. 14, 1956 5 Sheets-Sheet 3 03 a H i II I 7 I F q INVENTOR. LL'O/VA/Pfl A. WARD.

Patented Mar. 21, 1939 UNITED STATES PATENT OFFICE FURNACE STOKER Leonard A. Ward, Denver, Colo.

Application December 14, 1936, Serial No. 115,714

5 Claims.

This invention relates to a stoker for feeding coal to a furnace and while more particularly adapted for feeding fuel to household furnaces and heating plants it will be found useful 5 wherever a positive controlled fuel and air feeding device is required.

The principal object of the invention is to provide a stoker of this character which will occupy but a minimum of space; which will be quiet in operation; .which will positively and uniformly feed the fuel to the fire; which will automatically break and size the fuel to the proper feeding size; and which can be easily and accurately adjusted both as to air supply and coal supply.

Other objects and advantages reside in the detail construction of the invention, which is designed for simplicity, economy, and efficiency. These will become more apparent from the following description.

In the following detailed description of the in vention reference is had to the accompanying drawings which form a part hereof. Like numerals refer to like parts in all views of the drawings and-throughout the description.

In the drawings:

Fig. 1 is a plan view of the improved stoker with the hopper bottom thereof partially broken away to show the feeding mechanism.

Fig. 2 is a section through the stoker housing, taken on the line 2-2, Fig. 1, illustrating a side elevation of the operationg mechanism.

Fig. 3 is a vertical section, taken on the line il-3, Fig. 2.

Fig. i is a detail section through the upper extremity of the fuel feed tube.

Fig. 5 is a detail view illustrating the breaker plate employed in the invention.

Fig. 8 is a vertical section, taken on the line t-t, Fig. 3.

Fig. 7 is a detail section, illustrating the burner extremity of the stoker.

The entire coal. supply and operating mechanism is enclosed within an ornamental rectangular enclosing housing it], supported upon suitable legs ll. coal hopper i2 is formed into which coal may be fed through the open top of the housing it.

The bottom of the coal hopper it opens to a feed screw chamber it in which a feed screw it bill is positioned. The coal is prevented from arching over the feed screw chamber ill by means of an agitator it. At the discharge extremity of the feed screw chamber I3 is a feed chute it, the spout of which feeds the coal into the upper extremity of a feed tube ll. The feed tube ll is In the upper part of the housing it a.

the roller 36 against the cam ill.

inclined downwardly toward its discharge extremity and terminates over an air distributor 18 within the fire box of the furnace.

Air is fed to the air distributor l8 through a suitable conduit l9 from a blower 20. The blower is driven from an electric motor 2| which also operates the entire feed mechanism. The shaft of the motor 2i extends through the blower 20 as shown at 55 and terminates on the opposite side thereof in a worm 22, which is enclosed within a worm gear housing 23. The worm 22 acts to rotate the feed tube l'l through the medium of a worm gear 2t which is fixed to and rotates with the feed tube. The latter is carried in a bearing sleeve 25 which serves to support it and maintain it at the proper angle.

The feed screw It forces the coal along the chamber l3 and through a serrated breaker plate 26 provided with breaking teeth Zl. All large chunks of coal are broken up and reduced to small pieces as they enter the chute IS. The shaft of the feed screw extends through the chute it and is provided with a finger 28 which breaks loose any particles of coal caught in the breaker plate 26 and prevents packing in the chute. The upper extremity of the feed tube ll is also provided with an agitating finger 29 which extends within the chute iii to loosen any coal which may clog in the discharge thereof.

The feed screw Hi is intermittently rotated by 30 means of a friction wheel it The wheel 30' is mounted on one extremity of the feed screw shaft and is rotated from a reciprocating pawl lever 3i carrying a friction pawl 32. The lever it is also mounted on the feed shaft which serves as a pivot therefor. The panel 32 is pivoted to the lever by means of a suitable hinge pin 56. A return pawl 33 prevents return rotation of the ratchet wheel it.

The pawl lever 3:1 is reciprocated through the in medium of a connecting rod M from a bell crank lever 35, the other arm of which terminates in a roller 36 which rides against a cam ill on the feed tube ll. A coil spring 38 constantly pulls The eccentric i5 contour of the cam 31? imparts a rocking movement to the bell crank lever 35, which in turn imparts a similar'movement to the cam lever ti;

of the lever 3|. Thus, if the cam 40 is turned upwardly, the lever 3| will contact with it on its return stroke. This will hold the roller 36 out of contact with the cam 31 so that the rocker arm 35 will not receive a full reciprocation. In this way, the amount of regulated.

The agitator IS terminates on the exterior of the hopper I! in a slotted arm 4|, the slot of which rides over a crank pin 42 on the ratchet wheel 30. Thus, rotation of the ratchet wheel will move the agitator l5 to keep the coal flowing from the hopper to the feed screw II.

The amount of air can be regulated by means of an air regulating knob 42 which is operatively connected to a damper 43 on the intake of the blower 20. An auxiliary air pipe 44 may be placed from the conduit l9 extending into the chute I 6 to blow any fumes which may ascend in the feed tube downwardly and outwardly into the furnace. It is preferred, however, to place a suction pipe 55 from the suction side of the blower to the chute It to draw out any fumes which may collect in the feed tube and chute.

The delivery extremity of the feed tube is preferably formed with a helical agitator 45 which acts to distribute the incoming coal over the surface of the air distributor l8.

While a specific form of the improvement has been described and illustrated herein, it is desired to be understood that the same may be varied, within the scope of the appended claims, without departing from the spirit of the invention.

Having thus described the invention, what is claimed and desired secured by Letters Patent is:

1. Means for feeding solid fuel to a burner comprising: a feed hopper; a feed screw in the bottom of said hopper; a receiving chute for receiving the fuel from said screw; an inclined feed tube extending from said chute to said burner; means for rotating said feed tube; a cam surface carried by said feed tube; and a lever contacting saidcam to impart an intermittent rotation to said feed screw as said tube rotates.

2. Means for feeding solid fuel to a burner comprising: a feed hopper; a feed screw in the bottom of said hopper; a receiving chute for receiving the fuel from said screw; an inclined feed tube coal fed can be accurately extending from said chute to said burner; means for rotating said feed tube; a wheel on said feed screw; a pawl lever positioned adjacent said wheel; a pawl on said lever for rotating said wheel; a cam on said feed tube; and means riding on said cam for reciprocating said pawl lever.

3. Means for feeding solid fuel to a burner comprising: a feed hopper; a feed'screw in the bottom of said hopper; a receiving chute for receiving the fuel from said screw; an inclined feed tube extending from said, chute to said burner; means for rotating said feed tube; a wheel on said feed screw; a pawl lever positioned adjacent said wheel; a pawl on said lever for rotating said wheel; a cam on said fed tube; means riding on said cam for reciprocating said pawl lever; and

manually adjustable means for limiting the return movement of said pawl lever.

4. A stoker comprising; an enclosing, opentopped housing; a hopper bottom in the upper portion said housing; a feed screw chamber in said hopper bottom; a burner, a receiving chute at the extremity of said screw chamber; an inclined, rotatably mounted feed tube extending from said receiving chute to said burner; a blower positioned adjacent said feed tube; a conduit extending from said blower into said burner and terminating at the discharge extremity of said feed tube; an air distributor on the inner extremity of said conduit for receiving the fuel discharged from said tube; means for rotating said feed tube; a cam surrounding said feed tube; a lever riding against said cam; and means for transmitting the movement of said lever to said feed screw.

5. In a stoker of the type having a rotary inclined feed tube, means for feeding fuel into said feed tube comprisingra screw type conveyor positioned to i'eliver fuel to said feed tube; an annular eccentric am surrounding said feed tube; a cam follower bearing against said cam; a wheel on said feed screw; and a pawl actuated by said cam follower in contact with said wheel so that rotation of said feed -tube will cause said pawl to reciprocate said follower to cause the latter to intermittently actuate said wheel and through it said feed screw.

LEONARD A. WARD. 

